ultrasonography the spleen vca 341 dr. leeann pack [email protected]
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Spleen
Indications
Splenomegaly Palpable splenic mass Cranial abdominal organomegaly Lethargy, collapse Anemia, abnormal RBC’s
Spleen
Ultrasound Technique
Left side of body Head of spleen
– Under border of rib cage on left Body & tail of spleen
– Along left body wall– Ventral or lateral to left kidney
Scan sagittal & transverse
Spleen
Anatomy
Size of normal spleen variable– Assessed subjectively– Enlarged spleen may cross midline or
extend caudally to the bladder Parenchyma
– Homogenous, finely textured Echogenicity
– Dog: Spleen > liver > kidney– Cat: Spleen = liver > kidney
Spleen
Normal Spleen
Spleen
Anatomy
Capsule– Smooth, regular, VERY echogenic
Splenic veins– Only other structure normally visualized– Poorly visualized except near hilus
• “Whale tail”
– Enlargement subjective Hilus
– Check for lymphadenopathy
Spleen
Splenic Hilus
Spleen
Pathology
Diffuse splenomegaly– Congestion– Torsion– Inflammation/septicemia– Neoplasia
• Lymphosarcoma• Mast cell tumor
– Phenothiazine tranquilizers & barbiturate anaesthetics
– Extramedullary hematopoesis
Spleen
Pathology
Focal or multifocal splenic lesions– Hematoma– Infarcts– Cysts– Abscess– Nodular hyperplasia– Neoplasia
• Hemangioma• Hemangiosarcoma
Spleen
Diffuse Splenomegaly
Diffuse increase in echogenicity uncommon– Neoplastic (mast cell or lymphosarcoma)
Diffuse decrease in echogenicity more common– Congestion– Extra-medullary hematopoesis– Lymphosarcoma – Inflammation/ septicemia– Torsion
Normal echogenicity can occur with lymphosarcoma & mast cell tumor
Spleen
Non Homogenous
Spleen
Focal/Multifocal Lesions
More common than diffuse Anechoic
– Cysts• Hematoma/neoplasia
Hypoechoic– Neoplasia– Abscess– Acute infarct– Nodular hyperplasia
Spleen
Focal/Multifocal Lesions
Hyperechoic– Neoplasia– Abscess– Chronic infarct– Nodular hyperplasia
Mixed echogenicity– Neoplasia – Hematoma– Abscess– Nodular hyperplasia
Spleen
Splenic Mass
Spleen
Splenic Mass
Spleen
Splenic Infarct
Spleen
Torsion
Definitive diagnosis by ultrasound Characteristic appearance
– Severe, diffuse splenomegaly– Hypoechoic– Coarse & “lace-like”– Venous blood flow absent on Doppler– +/- hyperechoic venous thrombi
Lymphosarcoma can appear similar– Normal blood flow
Spleen
Torsion
Spleen
Neoplasia
Lymphosarcoma– Diffuse or focal/multifocal– Hypoechoic or hyperechoic– Can appear normal
Hematoma, hemangioma, hemangiosarcoma– Unable to differentiate– Focal– Hypoechoic, hyperechoic or mixed
Spleen
Lymphosarcoma
Spleen
Hemangiosarcoma
Spleen
Neoplasia
Other neoplasms – Mast cell tumor, leiomyoma, etc.
Presence of peritoneal effusion not a good indication of malignancy
Metastasis– Lungs, liver, lymph nodes (splenic,
hepatic, gastric)
Spleen
Echogenic Focal Lesions
Focal fat deposits– Especially cats– Surround hepatic veins (myelolipomas)
Fibrosis & calcification– Secondary to hematoma, chronic
infarcts or granulomas (histoplasmosis) Primary or metastatic neoplasia
Spleen
Definitive Diagnosis
Ultrasonic appearance of most splenic diseases non-specific
Consider history, signalment, clinical signs
Fine needle aspirate useful Biopsy generally not performed
Spleen
Rupture
Free fluid within the abdomen– Often echoic (due to blood cells)– May be anechoic
Most likely a tumor Cannot rule out hematoma
Spleen
Thrombosis
Spleen
Splenic Thrombus
Spleen
Myelolipoma